Apparatus for removing the excess material obtained when trimming the top side of plastic foam concrete blocks

ABSTRACT

A device for removing the material trimmed from the top side of plastic foam concrete blocks in which a suction box is lowered onto and travels across the concrete block. The suction box has a grid with a plurality of fine openings therein all being connected to a suction fan which generates a negative pressure in the suction box.

United States Patent 1 3,571,839

[72] Inventors Wilfried Hartmann References Cited Lindacherueg 15, Emmering near UNITED STATES PATENTS Fur enf 1,322,361 11/1919 Sherman l5/422UX Josef vogele, Albrecht-Durer-Strasse 3, 2,531,920 11/1950 Raminger 15/422x Flrstenfeldbmck, Germ 3,420,004 1/1969 OBrien 51/273x [21] P 1 FOREIGN PATENTS [22] PM 1968 376,356 6/1907 France 15/418 Patented Mar. 23, 1971 I 150 789 6/1963 G 5/301 NovI l5 elmany [33] Germany Primary Examiner-Walter A. Scheel [31] P 16 83 837.2 Assistant ExaminerC. K. Moore Attorney-Woodhams, Blanchard and Flynn [54] APPARATUS FOR REMOVING THE EXCESS MATERIAL OBTAINED WHEN TRIMMING THE TOP SIDE OF PLASTIC FOAM CONCRETE BLOCKS 7 Claims, 4 Drawing Figs. [52] U.S.Cl 15/303, ABSTRACT: A device for removing the material trimmed 15/307, 214/ l, 294/64 from the top side of plastic foam concrete blocks in which a [51] Int. Cl A47l5/38 suction box is lowered onto and travels across the concrete [50] Field of Search 15/301, block. The suction box has a grid with a plurality of fine 306, 308,415,418,422;51/273;25/(lnquired); openings therein all being connected to a suction fan which /(Inquired); 294/64; 214/1 (BS), 1 (BS)2 generates a negative pressure in the suction box.

Mi li REMQVTNG 'llll il MATEERHAL til llTfitlhl WHEN TlilMMilhlG Tlllilil TUE SlllDl'E @F i lllASTliC FilAli l CTJINQRETE hlbtltlltb This invention relates to an apparatus for removing the excess material obtained when trimming the top of foam concrete blocks.

Foam concrete blocks are cast in large boxes. Each block is then transferred to the table of a cutting machine where it is cut into slabs and the like by means of a cutting device. During this procedure a layer, which has a thickness of between ap proximately 3 to cm. (1.2 to 4 inches), is cutoff, by means or a horizontal cutting wire, from the surface of the foam concrete block while still in a plastic state.

Hitherto this so-called excess material was swept off or withdrawn by cleaning apparatus from the top after the concrete block had been cut into slabs or bricks. in this cleaning procedure the excess material falls, for example, onto conveyor belts which are arranged in pits extending laterally of the cutting installation. These conveyor belts remove the material away from the cutting installation and transport it to a processing plant.

in this known method of cleaning the top of the block the danger exists that the block may be damaged, particularly at the edges, thus making the cut slabs partly or totally unusable.

A further disadvantage consists in that the sweeping or removal procedure is time consuming, requires several workmen and in addition does not result in complete cleaning of the top surface of the block.

The object of the present invention is to provide an apparatus of the type mentioned above by means of which, with the least possible use of implements and in a single operation, all excess material can be removed from the top surface of the block, while, at the same time, avoiding any damage to the delicate foam concrete block.

This object is achieved, according to the invention, by a suction box which can be lowered onto and be moved across the top of the concrete block, the lower surface of the said suction box which faces the concrete block consisting of a suction grid having a plurality of line openings and being connected via connecting pipe lines to a suction fan or the like which generates a negative pressure.

The suction box may have roughly the same shape in plan as the largest concrete block which can be cast in a particular works and is preferably of relatively flat construction, since, for a given suction fan output, the negative pressure in the suction box required to lift the excess material is more rapidly reached the smaller is its volume. The lowest limits for the height dimensions of the suction box are therefore only determined by requirements of strength as well as the requirement that the air current caused by the suction fan is not subject to large losses.

The necessary negative pressure in the suction box depends essentially upon the weight to be carried, that is upon the specific gravity and the volume of the excess layer. With a specific gravity of approximately 1 and an average thickness of the layer of between 3 and 10 cm. (1.2 to 4 inches) a pres sure difference between the outside atmosphere and the interior of the suction box of only 0.03 kgJcmF, corresponding to 0.03 atmospheres (.427 pounds per sq. inch), has proved to be sufficient to aspirate and effectively hold the excess materiall. With this negative pressure comparatively large excess material up to approximately cm. (6 inches) can be aspirated and held.

The size of the opening as well as the width of the webs remaining between them should be small as possible as the excess material breaks up during cutting and also during the suction procedure and partially into very small individual pieces. Suction grids have proved to be satisfactory in which the openings have a width of approximately 1 mm.(0.04 inch).

in order also to be able to use the apparatus on those cemerit blocks having a smaller plan area than that of the suction grid, there is provided, according to the invention, means by which that part of the exposed suction grid which extends beyond the concrete block can be covered.

Further characteristics and advantages of the invention are explained in more detail below by means of the embodiment illustrated in the accompanying drawings in which:

Flt l is a suction box seen from below;

2. is a side elevation of a flat suction box arranged on a supporting frame, before being lowered onto a trimmed concrete block;

FIG. 3 is a view of a winding device for winding up a roller blind cover taken along the line ill-dill of FIG. l; and

FIG. 4 shows the details of a suction grid.

in the drawings (H65. 11 and 2) a rectangular suction box 33 is illustrated by way of an example. This suction box is made up of an angle iron frame 1 and a cover plate 2 and is closed at the bottom by means of the suction grid t. The suction box 3 is suspended from reinforcing struts d from a support frame 6 of rooflike construction. On top of the reinforcing struts .b, loops or eyelets '7 are arranged by which the supporting frame 6 may be suspended and moved by a lifting crane in the direction indicated by the two arrows d.

The supporting frame 6 also accommodates a suction fan 9 arranged above the suction box 3, the suction side of the said fan being connected by a pipeline it) which passes through the cover plate 2 to the inside of the suction box 3, its exhaust outlet lll leading to atmosphere. In the illustrated embodiment the fan 9 is driven by an electric motor 12.

At one end of the suction box 3 there is fitted a roller blind cover l3 which'can lie pulled in a longitudinal direction over the lower side of the suction grid 5. The roller blind cover is retractable by means of the winding device l l actuated by the crank handle 15. The free end 16 of the roller blind cover is reinforced by the strap 17 which is conveniently of L-shaped cross section. The strap i7 is secured at either end to one of two endless chains 1.9 arranged on both sides of the suction box and driven by the crank handle 15. For this purpose on both ends of the winding device and coaxially therewith, sprockets id are provided over which the chains l9 run on the one end of the device. On the other end the chains run over freely rotatable guide sprockets 2b which are arranged on both sides of the suction box. These sprockets also serve as tensioners for the chains 19.

in H6. 3 an embodiment of a winding device 30 is illustrated by means of which a continuous and even tightening effect and thus a perfectly tight fitting of the roller blind against the suction grid may be achieved. A hollow winding drum 30 is fitted concentrically with and freely rotatably on a central shaft 35 and connected thereto by means of spiral springs 32. The guide sprockets lb for the endless chains are arranged on the shaft 33d. For reasons of clarity this latter arrangement is not illustrated in H6. 3. The roller blind cover which is wound onto the winding drum and provided with an angle section strap Ill secured to the chains l9 which are also not illustrated is equally prestressed by the tensioned spiral springs in any position of the roller blind cover.

MG. 4 shows a suitable arrangement of the suction grid. A time mesh sieve dil manufactured, for example, of stainless steel wire with a mesh of approximately 1 mm. (0.04 inches) forms the suction grid proper against which the aspirated excess material abuts. As such line sieves generally do not have sufficient rigidity, a stronger supporting grid M of stronger wire and a larger mesh size is secured to the sieve ltl at several points distributed over the sieve surface, for example by means of binding wire. As suction grids, fine nylon nets or expanded metal nets are also suitable.

The top cover of the suction box preferably consists of a plastic covered fabric so that it is impervious to air and unaffected by the foam concrete material.

The mode of operation of the apparatus is as follows: After cutting off the excess material 50 (MG. 2) the suction box 3 which has a breadth corresponding to the breadth of the concrete block, is lowered, with the suction fan running, over the concrete block 51 in such a manner that it is a short distance above the bloclt. Care should be taken that the left end of the suction box terminates at the corresponding end surface of the concrete bloclr.

On the other end the effective surface of the suction grid is adjusted to correspond to the length of the concrete block by appropriately pulling out the roller blind cover. By the negative pressure produced by the suction fan the excess material is lifted onto the suction sieve where it adheres in position. With the suction fan running the support frame 6 is lifted, for example, by lifting a crane and conveyed to the position where the excess material can be offloaded, possibly to a hopper situated adjacent the cutting machine, where a conveyor or the like is located below the said hopper which transports the foamed concrete bulk to a processing plant. After the suction fan is switched off, the excess material drops off and the suction box is again ready for use.

As the apparatus according to the invention is not lowered onto the foamed concrete block, but rather to a distance of about 3 cm.( 1.2 inches) above it, it doesnot make any contact at all with the concrete block so that any damage to the block during the removal of the excess material is thus effectively avoided.

We claim:

1. Apparatus for removing the excess material obtained from cutting the top side of foamed concrete blocks, comprismg:

a suction box adapted to be lowered into close association with the concrete block and be moved across the top surface thereof, the underside of the suction box which is adapted to face the concrete block having a plurality of openings therein;

a suction fan connected to the suction box for generating a negative pressure;

a drum rotatably supported on the suction box; and

a flexible cover foil, one end of which being wound onto the rotatable drum, the other free end thereof being guided along both longitudinal sides of the suction box and adapted to cover selected ones of the openings.

2. Apparatus according to claim 1, including spring means for maintaining the cover foil tensioned.

3. Apparatus according to claim 2, wherein the free end of the cover foil is guided for movement along the suction box by two pairs of longitudinally spaced chain wheels on each side of the suction box, one of the chain wheels in each pair being operatively connected in association with the rotatable drum, a chain guided by each of said two pairs of longitudinally spaced chain wheels, the free end of the cover foil being attached to the chains for movement toward and away from the rotatable drum to cover selected ones of the openings, and a hand crank drivingly connected to said rotatable drum for drivingly rotating same.

4. Apparatus according to claim 3, wherein said rotatable drum is freely rotatably supported on a shaft, said shaft being adapted to be rotatably driven by a crank handle, the pair of chain wheels operatively connected in association with the rotatable drum being fixedly mounted to said shaft, said shaft and said drum being interconnected by spiral springs.

5. Apparatus according to claim 1, wherein the cover foil consists of a fabric coated with plastic.

6. Apparatus according to claim 1, wherein the openings in the underside of the suction box are defined by a suction grid consisting of a wire sieve. I

7. Apparatus according to claim 6, wherein the suction grid consists of a fine meshed wire sieve and a coarse support grid arranged thereabove and connected at several places to the wire sieve. 

1. Apparatus for removing the excess material obtained from cutting the top side of foamed concrete blocks, comprising: a suction box adapted to be lowered into close association with the concrete block and be moved across the top surface thereof, the underside of the suction box which is adapted to face the concrete block having a plurality of openings therein; a suction fan connected to the suction box for generating a negative pressure; a drum rotatably supported on the suction box; and a flexible cover foil, one end of which being wound onto the rotatable drum, the other free end thereof being guided along both longitudinal sides of the suction box and adapted to cover selected ones of the openings.
 2. Apparatus according to claim 1, including spring means for maintaining the cover foil tensioned.
 3. Apparatus according to claim 2, wherein the free end of the cover foil is guided for movement along the suction box by two pairs of longitudinally spaced chain wheels on each side of the suction box, one of the chain wheels in each pair being operatively connected in association with the rotatable drum, a chain guided by each of said two pairs of longitudinally spaced chain wheels, the free end of the cover foil being attached to the chains for movement toward and Away from the rotatable drum to cover selected ones of the openings, and a hand crank drivingly connected to said rotatable drum for drivingly rotating same.
 4. Apparatus according to claim 3, wherein said rotatable drum is freely rotatably supported on a shaft, said shaft being adapted to be rotatably driven by a crank handle, the pair of chain wheels operatively connected in association with the rotatable drum being fixedly mounted to said shaft, said shaft and said drum being interconnected by spiral springs.
 5. Apparatus according to claim 1, wherein the cover foil consists of a fabric coated with plastic.
 6. Apparatus according to claim 1, wherein the openings in the underside of the suction box are defined by a suction grid consisting of a wire sieve.
 7. Apparatus according to claim 6, wherein the suction grid consists of a fine meshed wire sieve and a coarse support grid arranged thereabove and connected at several places to the wire sieve. 